WebGIS应用中的远程对象预获取策略研究

Research of Prefetch Policies for Remote Objects in WebGIS Application

WebGIS系统采用什么样的对象预获取策略取决于用户的预获取模式.本文首先介绍了基于分区的对象预获取策略的基本概念,然后针对具有空间局域性的用户获取模式,提出了一种基于希尔伯特曲线的预获取策略,主要讨论了如何解决预获取策略中的两难问题,并给出了算法和性能分析.实验结果表明,该方法在确保减少平均响应时间的前提下,能有效地降低网络流量增加率.

In this paper, we first introduces some fundamental concepts of prefetch policies for remote objects based upon partitions, then we propose a Hilbert curve-based prefetch policy used for the user access pattern with spatial locality, and discusseing how to resolve the dilemma in prefetch policies. The performance analysis of the algorithm is given. The result show that this policy can reduce fractional increase in network traffic under the condition that the average response time is reduced.